Adjustable arbor



Aug. 15, 1950 VAN BEVER 2,518,508

ADJUSTABLE ARBOR fFil d Aug. 9, 1945 INVENTOR EDMOND VAN BEVER ATTORNEY Patented Aug. 15, 1950 ED PATENT Flifi'E;

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This inventionrelates to arborsor: mandrel's and more particularly to an adjustment for arbors or mandrels of the expansible t'ypesuch-asare commonlyused in supporting workpieces on lathes and the like for turning, grind=- ing, and polishing-:operatinnsz:

It is. an object of thepresent invention to provide an expansion arbor which is. especially useful. in supporting long workpieces or workpieces hav'-' ing only partia-l internal bores therein, i e., bores WhiChl-dOI not extend throughethe workpiece;

It-is another object of therinvention too-provide am. expansion type of arborwitlri aeprimary universally operable, expansion; adjustmentmeans and a secondary,,truing or centering, individually operable, adjustment means.

It is. a: further object Oil the invention tnrproevid'ei a. tool of. the. above. character? that: comprised of a few, simple, and inexpensive parts arranged to be easily assembled and which may be readily adjusted to accommodate workpieces of difierent internal diameters.

With the above and other objects and features in view, the invention will now be described with reference to the accompanying drawings which illustrate a preferred embodiment of the invention and will be pointed out in the claims.

In the drawings:

Fig. 1 is a side elevation of the improved arbor, certain parts being broken away for clearness, and

Fig. 2 is a sectional elevation taken on the line II--II of Fig. 1.

The arbor or mandrel comprises a shaft l threaded adjacent to the opposite ends as at I! and I4. Between the threaded sections, the shaft is formed like a truncated pyramid by four, tapering, slabbed sides I6 extending longitudinally of the shaft. Each side is has mounted thereon for longitudinal sliding movement, a segment l8, the internal face of which is formed on an angle corresponding to the'angle of the taper of the side.

The external faces of the segments are curved widthwise and together, in complement, provide a cylindrical, workpiece, engaging surface broken only by the clearance spaces 22 provided between the segments to permit of their being adjusted longitudinally along the sides l6. The segments are yieldingly held in assembled relation on the shaft ill by a split retainer ring 24 of spring stock. The ring 24 encircles the segments and fits within aligned annular grooves 25 provided in the external faces 20. ,The depth of the grooves 25 is sufficient to receive the ring 2-; wilds: clearances-between thezperiphery of: thtslsingz and: the faces; 211:;

' ofthelsegmentsis: substamtiallarlessa the lengths of the tapered sides I63. Home by movingithe segments as a group; bodily, along thez'sides Hie against the. direction: of, the-tapers, the diameter across the faces: Zwmay: be and: by moving the; segments. the directiom ofe thez taper. the diameter; may be: decreased.

- this manner.- the arbor: is adjusted to supports workpieces that have bones of; different-internals diameters.

The means; for: making: the prima-ry, universal? adj ustmentof the segments; l 8; comprisesrasspacr ing collar 26 having a tapmedzborernthatlaccomz modates. with clearance the leftlendiof. shafit I20. A1 nut. 31% threaded; one the:- portiorr M; of. the shaft; may; be turned; om the: threadstosforce thercnllan 2'52 againsathe. segments; to move: thenn. unifnmnlyr as a group, further outwardly or the nut may be backed off to permit the segments to be drawn closer together under the action of the spring 24.

The means for making the individual or secondary adjustment of the segments l8 comprises a disk or plate 32 threadedly mounted upon the threaded section l2. The plate 32 is arranged to be secured in adjusted position in spaced relation away from the larger end of the tapered section of the shaft ID by a lock nut 34. Each segment l8 has threaded in its end lying opposite to the end that is engageable by the collar 26, a cap screw 36. The shanks of the cap screws 36 pass with clearance through spaced slots 38 provided in the plate 32. Consequently, when the collar 26 is moved toward the right to expand the segments as above described, this movement is not interfered with by the screws 36, the latter merely sliding idly through the slots 38 during such movement. When, however, it is desired to true up or center a workpiece, this may be readily effected by individually adjusting the segments l8. This is done by letting off and taking up on the appropriate screws 36, the cap of the taking up screw bearing against the outer surface of plate 32 for this purpose.

The slight increment of movement of the segment or segments necessary for the truing up operation is permitted by the yield of spring 24.

Apart from the advantages derived from the use of the tool in efiecting a very fine degree of adjustment in truing or centering workpieces, the tool has been found extremely useful in mountin relatively long workpieces or workpieces having only partial bores. In the latter instances, a primary or approximate adjustment of the segments to the internal diameter of the bore of the workpiece is made by turning the nut 30. The tool is then inserted within the bore. Now, even though the nut 30 is inaccessible either because of the length of the workpiece or because the bore does not extend therethrough, the final gripping adjustment may be readily effected by taking up on each of the screws 36.

The invention described herein may be manufactured and used by or for the Government ofthe United States of America for governmental v purposes without the payment of any royalty thereon or therefor. Having described my invention what I claim as novel and desire to protect by Letters Patent of the United States is:

1. An expansion arbor comprising a body portion of truncated pyramidal shape having threadin said plate, the heads of said screws being incontacflwith the face of said plate furthest removed from said segments to move each of said segments individually.

2. An expansion arbor comrising a body portion of truncated pyramidal shape having threade'd shaft extensions on either end thereof, a plurality of segments mounted for longitudinal 4 sliding movement along the faces of said body portion, a resilient retaining ring maintaining said segments in position on said faces, a nut and spacing collar associated with the threaded shaft extension on the smaller end of said body portion operable universally to move said segments along said faces, said retaining ring in cooperation with the shape of said body portion tending to maintain said segments in contact with said spacing collar regardless of the direction of adjustment of said collar, a plate adjustably secured to the other threaded shaft extension in spaced relation with said body portion, said plate having a plurality of spaced slots about the periphery thereof, a plurality of cap'screws, each of said screws being threaded into one of said segments and passing with clearance through one of said spaced slotsin said plate, the heads of said screws being in contact with the face of said plate furthest removed from said segments, whereby said segments may be moved individually toward said plate gradually to increase the diameter of said arbor.-

- EDMOND VAN BEVER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 465,075 I Grantland Dec. 15, 1891 480,435 'McGraw Aug. 9, 1892 1,919,239 McFall July 25, 1933 FOREIGN PATENTS Number Country Date Great Britain 1387 Certificate of Correction Patent No. 2,518,508 August 15, 1950 EDMOND VAN BEVER It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 2, line 25, for threadedly read threadably; column 3, line 22, after the Word resilient insert retaining;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Ofifice.

Signed and sealed this 14th day of November, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oommz'ssz'oner of Patents. 

